GENERAL OVERVIEW: The Flow Cytometry Core at NEI provides flow cytometry analytical and sorting equipment and services to the NEI Intramural community. It utilizes and develops state-of-the-art sample preparation, data acquisition and analysis, and sorting procedures in collaborative research projects. Provides training to students, fellows, and principal investigators on sample preparation, staining, and post-sort handling. Assesses technical research needs and recommends recruitment of the appropriate staff and acquisition of the equipment needed to meet those needs. The core also supports NIH intramural research outside NEI by processing samples for laboratories without access to flow cytometry instrumentation and collaborations with the Foundation for Advanced Education in the Sciences SERVICES PROVIDED THE CORE: This year, 63 (sixty-three) individuals from 13 (thirteen) different laboratories used the facility. These services and collaborative services were performed for 12 Principal Investigators (PIs) from 8 NEI labs (ERPD, LI, LRCMB, MSF, N-NRL, RN, OGVFB and UNGIRD), plus 4 PIs from 4 other institutes at NIH (NCI, NIAID, NICHD and NIDCD). This year the core performed 1,250 hours of sorting and over 15,000 samples were analyzed. Among the techniques now in use within the core are methods for phenotyping live cells, gene expression detection through fluorescent reporter genes, monitoring membrane and DNA content changes due to apoptosis or proliferation, measurement of intracellular proteins and quantification of soluble proteins. The work involving human tissues includes the sorting of peripheral blood mononuclear cells to study their cytokine production, genotype and DNA or RNA expression. The sources are blood, buffy coat, and white cells. Some analytical work had been done with eye fluids, eye tissue specimen, protein, and tears. The National Eye Institute made a great investment in biosafety with the addition BD FACSAria Fusion flow cytometer equipped with a fully integrated biosafety cabinet. This sorter meets the recent NIH's operator and sample protection requirements as well as global standards for bioprotection for processing human samples. No human tissues were stored by the core. The Core encourages, but does not require, users to acknowledge the Core contribution in their publications. The following are examples of the publications that used NEI Flow Cytometry Core resources: Ma W, et al. Absence of TGF signaling in retinal microglia induces retinal degeneration and exacerbates choroidal neovascularization. eLife. 2019;8:e42049. Sharma R, et al. Clinical-grade stem cell-derived retinal pigment epithelium patch rescues retinal degeneration in rodents and pigs. Sci Transl Med. 2019 Jan 16;11(475). pii: eaat5580. doi: 10.1126/scitranslmed.aat5580. Uygur B et al. Interactions with Muscle Cells Boost Fusion, Stemness, and Drug Resistance of Prostate Cancer Cells. Mol Cancer Res. 2019 Mar;17(3):806-820. doi: 10.1158/1541-7786.MCR-18-0500. Epub 2018 Dec 26. Mary J. Mattapallil, et al. Interleukin 22 ameliorates neuropathology and protects from central nervous system autoimmunity,Journal of Autoimmunity,Volume 102, 2019,Pages 65-76, ISSN 0896-8411. So Jin Bing et al. AS101 ameliorates experimental autoimmune uveitis by regulating Th1 and Th17 responses and inducing Treg cells. Journal of Autoimmunity Volume 100, June 2019, Pages 52-61 Cancan Lyu et al. TMP778, a selective inhibitor of RORt, suppresses experimental autoimmune uveitis development, but affects both Th17 and Th1 cell populations. Eur. J. Immunol.48-11 0014-2980 doi:10.1002/eji.201747029 ChengRong Yu, et al. Production of IL35 by Bregs is mediated through binding of BATFIRF4IRF8 complex to il12a and ebi3 promoter elements. J Leukoc Biol 104 6 0741-5400 doi:10.1002/JLB.3A0218-071RRR TRAINING: Several formal training sessions were offered by the Core to the NEI community. These courses included: Introduction to Flow Cytometry, Advanced Techniques (Ex. Apoptosis applications), Analytical Instrument Operation and Data Analysis with FloJo Software. The Core stuff received about 100 hrs. or training a year in flow cytometry. The Core stuff provided about 50 hrs of training to the NEI community and 60 hrs of training through FAES to the NIH community.